Databus MOSS

The Databus MOSS (Metadata Overlay Search System) is a system of creating modular metadata extensions for the metadata graphs provided by Databus entries. The general idea is that a Databus instance provides stable identifiers for your files along with the most basic metadata for file usage (format, compression, licensing). However, more domain or file-type specific metadata is often needed. MOSS provides a system for the management of additional metadata graphs. With MOSS, you can:

• Create schema for metadata extensions
• Create and manage additional metadata graphs
• Tailor a flexible indexed searcher directly to your specific RDF-metadata
• Enjoy enhanced data retrieval based on your metadata entries

Here you can find instructions for deployment of a MOSS instance with Docker and examples to get you started. The code for the two main components (server and frontend) are held in separate repositories.

• MOSS-Server: https://github.com/dbpedia/databus-moss-server
• MOSS-Frontend: https://github.com/dbpedia/databus-moss-frontend

Deployment and Example

Run

git clone https://github.com/dbpedia/databus-moss.git
cd databus-moss

Adjust the environment variables in the .env file (see Environment Variables).

Then run

docker compose pull
docker compose up

Go to

http://localhost:3000

MOSS configuration lives in ./config and is mounted into the server container.

Containers

ghcr.io/dbpedia/databus-moss-frontend:dev Frontend using Svelte. Exposed on ${MOSS_FRONTEND_PORT} (default 3000).

ghcr.io/dbpedia/databus-moss-server:dev Server with MOSS API. Expose port 8080 when running as standalone API server.

ghcr.io/dbpedia/gstore:dev Gstore backend proxy.

openlink/virtuoso-opensource-7:latest Triple store backend.

Environment Variables

Create a .env file in the project root:

Variable	Example	Description
MOSS_FRONTEND_PORT	3000	Host port mapped to the frontend container.
MOSS_BASE_URL	https://moss.example.org	Public base URL of the MOSS instance. Used for generating resource identifiers. Most commonly the public URL of the frontend.
VIRTUOSO_DBA_PASSWORD	...	Password for the Virtuoso dba user. Also used by gstore to connect to Virtuoso.
AUTH_OIDC_ISSUER	https://auth.dbpedia.org/realms/dbpedia	OpenID Connect issuer URL of your identity provider.
AUTH_OIDC_CLIENT_ID	moss-dev	OIDC client ID registered with the identity provider.
AUTH_OIDC_CLIENT_SECRET	...	OIDC client secret for the registered client.
AUTH_SECRET	...	Secret used by the frontend to sign and encrypt session cookies. Generate a random string.
AUTH_ADMIN_USERS	user1,user2	Comma-separated list of usernames granted admin access in MOSS.
AUTH_ORIGIN	https://moss.example.org	Public URL of the frontend. Used for OIDC redirect validation. Must match how users access the app.